JP2012058506A - Optical material, tin oxide fine particle dispersion, tin oxide fine particle dispersion coating material, method for manufacturing optical material, high refractive index film, and antistatic film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical material which has a high content of tin oxide fine particles with respect to a resin, has a high refractive index and excellent light transmission characteristics, does not impair transparency even in an optical path length of 10 μm or more, has a sufficient film strength, and can be inexpensively manufactured, and to provide a tin oxide fine particle dispersion, a tin oxide fine particle dispersion coating material, a method for manufacturing an optical material, a high refractive index film, and an antistatic film.SOLUTION: In the optical material formed by dispersing tin oxide fine particles into a resin, the dispersion particle size of the tin oxide fine particles is 10 nm or more and 90 nm or less. The surfaces of the tin oxide fine particles are modified with a surface treatment material of 30 mass% or less with respect to the tin oxide fine particles. The content of the tin oxide fine particles is 20 mass% or more and 80 mass% or less.

Description

  The present invention relates to an optical material, a tin oxide fine particle dispersion, a tin oxide fine particle dispersion paint, a method for producing an optical material, a high refractive index film, and an antistatic film, and more particularly, a plasma display (PDP) and a liquid crystal display (LCD). It is suitably used for various flat panel displays (FPD) such as electroluminescence displays (ELD), and it is possible to impart an antireflection effect and an antistatic effect to the display surface of these FPDs, as well as a touch panel. An optical material capable of forming a film having sufficient light transmission characteristics and strength even when formed, a tin oxide fine particle dispersion and a tin oxide fine particle dispersion paint suitable for use in forming this optical material, and this Manufacturing method of optical material, high refractive index film formed using this optical material, and antistatic film Is shall.

Conventionally, in various flat panel displays (FPD) such as a plasma display (PDP), a liquid crystal display (LCD), and an electroluminescence display (ELD), external light and images are reflected on the display surface of the image display unit. Thus, it has been pointed out that the image displayed on the image display unit becomes unclear or the inside of the image display unit becomes unclear.
In addition, the transparent resin base material used in these FPDs is easily charged with static electricity, and thus the displayed image is difficult to see due to dust adhering to the display surface due to the static electricity. There are also problems.
Therefore, in the FPD, in order to solve these problems, an optical thin film having an antireflection effect and an antistatic effect is provided on the image display unit.

On the other hand, in recent years, with the increase in size and price of various FPDs, there has been a demand for an increase in the size and cost of the optical thin film provided in the image display unit.
Therefore, a technology for sticking a transparent film with an antistatic / antireflection film to the display surface of the image display unit of the image display device for reasons such as being easy to handle upsizing, easy to manufacture, and capable of reducing manufacturing costs. Has been proposed.
This transparent film with an antistatic / antireflection film uses a laminated film in which a high refractive index film and a low refractive index film are combined to provide an antireflection function, and also forms a high refractive index film. Therefore, zirconium oxide (zirconia) or titanium oxide (titania) is used as a high refractive index material to be added (Patent Document 1).

JP 2008-185756 A

By the way, in the conventional transparent film with an antistatic / antireflection film, in order to further improve the antireflection characteristic, the refractive index of the high refractive index film is increased or the refractive index of the low refractive index film is further decreased. However, when increasing the refractive index of the high refractive index film, it is necessary to further increase the amount of oxides such as zirconium oxide (zirconia) and titanium oxide (titania). However, a further increase in oxide causes a decrease in film quality and the like. In addition, since the oxide is relatively expensive, an increase in manufacturing cost cannot be avoided.
On the other hand, when further reducing the refractive index of the low refractive index film, it is necessary to further increase the addition amount of hollow silica or the like, which is a low refractive index material. In addition, since the hollow silica is relatively expensive, an increase in manufacturing cost cannot be avoided.
In recent years, a transparent film with an antistatic / antireflection film has been severely demanded for cost reduction, and has not been fully supported.

  Furthermore, in recent years, a so-called touch panel in which a touch pad is formed on an FPD has been widely used. In this touch panel, the surface protection of the image display unit is performed in order to directly operate the touch pad on the image display surface. It is required that the film not only has a sufficient antireflection effect and light transmission property, but also has a film strength that can sufficiently withstand repeated operations. In order to improve the film strength, it is effective to increase the film thickness, but since the increase in the film thickness decreases the light transmission characteristics, the film has sufficient film strength and excellent light transmission characteristics. There was a problem that it was difficult to obtain a protective film.

  The present invention has been made to solve the above-described problems, and has a high content of tin oxide fine particles with respect to a resin, a high refractive index, excellent light transmission characteristics, and transparency even in an optical path length of 10 μm or more. It is an object to provide an optical material in which tin oxide fine particles and a resin are combined and integrated, which has a sufficient film strength and can be manufactured at a low cost. In addition, a tin oxide fine particle dispersion in which tin oxide fine particles are dispersed in a dispersion medium, which has a high refractive index and excellent light transmission characteristics, and a tin oxide fine particle dispersed paint in which the tin oxide fine particle dispersion and a resin are dispersed and mixed, It is an object of the present invention to provide a method for producing an optical material using a tin oxide fine particle-dispersed paint, a high refractive index film and an antistatic film to which the optical material is applied.

  As a result of intensive studies to solve the above problems, the present inventors have selected tin oxide fine particles as inorganic oxide fine particles, and the dispersed particle diameter of the tin oxide fine particles when the tin oxide fine particles are dispersed in the resin. If the surface of the tin oxide fine particles is modified to be 10 nm or more and 90 nm or less with a surface treatment material of 30% by mass or less of the tin oxide fine particles, the dispersed particle size of the inorganic fine particles in the optical material can be increased. It was found that the refractive index can be increased while maintaining the transparency of the optical material strictly. Further, when the tin oxide fine particles are dispersed in the dispersion medium, by controlling the dispersion particle diameter of the tin oxide fine particles, a tin oxide fine particle dispersion with transparency maintained can be obtained. In a tin oxide fine particle dispersed paint obtained by dispersing and mixing a fine particle dispersion and an uncured resin, a tin oxide fine particle dispersed paint maintaining transparency can be obtained by controlling the dispersed particle size of the tin oxide fine particles. I found out. By curing this tin oxide fine particle-dispersed paint, an optical material can be easily obtained, and a high refractive index film having a high refractive index while maintaining transparency, and also has an antistatic function because it has conductivity. The present inventors have found that an antistatic film imparted with the above can be easily obtained, and have completed the present invention.

  That is, the optical material of the present invention is an optical material obtained by dispersing tin oxide fine particles in a resin, and the dispersed particle diameter of the tin oxide fine particles is 10 nm or more and 90 nm or less, and the surface of the tin oxide fine particles is The tin oxide fine particles are modified with a surface treatment material of 30% by mass or less.

  The content of the tin oxide fine particles is preferably 20% by mass or more and 80% by mass or less.

  The tin oxide fine particle dispersion of the present invention is a tin oxide fine particle dispersion obtained by dispersing tin oxide fine particles in a dispersion medium, and the dispersed particle diameter of the tin oxide fine particles is 10 nm or more and 90 nm or less. The surface of the tin fine particles is modified with a surface treatment material of 30% by mass or less of the tin oxide fine particles.

  The tin oxide fine particle dispersed paint of the present invention is a tin oxide fine particle dispersed paint obtained by dispersing and mixing the tin oxide fine particle dispersion of the present invention and an uncured resin, and the tin oxide fine particle dispersed paint in the tin oxide fine particle dispersed paint. The dispersed particle diameter of the fine particles is 10 nm or more and 90 nm or less.

  The method for producing an optical material of the present invention is characterized in that the tin oxide fine particle dispersed paint of the present invention is cured.

  The high refractive index film of the present invention is formed using the optical material of the present invention.

  The antistatic film of the present invention is formed using the optical material of the present invention.

  According to the optical material of the present invention, an inexpensive tin oxide fine particle is selected as the high refractive index material, the dispersed particle diameter of the tin oxide fine particle is set to 10 nm or more and 90 nm or less, and the surface of the tin oxide fine particle is coated with the tin oxide fine particle. Since it is modified with a surface treatment material of 30% by mass or less of the fine particles, light path length of 10 μm or more is suppressed while suppressing light scattering by the tin oxide fine particles, particularly light in a wavelength band of 350 nm to 800 nm in the visible light region. In this case, sufficient transparency can be secured. Therefore, it is possible to provide an optical material having a high refractive index while maintaining transparency.

Moreover, since it has sufficient film | membrane intensity | strength, when it applies to a touch panel etc., it can fully endure repeated operation.
Moreover, since the tin oxide fine particles have conductivity, antistatic properties can be imparted.
Further, since the tin oxide fine particles are less expensive than zirconium oxide (zirconia), titanium oxide (titania), hollow silica, and the like, the manufacturing cost of the optical material can be reduced.

According to the tin oxide fine particle dispersion liquid of the present invention, an inexpensive tin oxide fine particle is selected as the high refractive index material, and the dispersed particle diameter of the tin oxide fine particle is set to 10 nm or more and 90 nm or less. Since the surface treatment material is modified with 30% by mass or less of the tin oxide fine particles, the transparency of the dispersion can be maintained even when the content of the tin oxide fine particles is increased.
Therefore, by producing a tin oxide fine particle dispersed paint using this tin oxide fine particle dispersion, it is possible to easily and inexpensively obtain a tin oxide fine particle dispersed paint having a high content of tin oxide fine particles and maintaining transparency. it can.

According to the tin oxide fine particle dispersed paint of the present invention, the tin oxide fine particle dispersion of the present invention and an uncured resin are dispersed and mixed, and the dispersed particle diameter of the tin oxide fine particles in the tin oxide fine particle dispersed paint is 10 nm. Since the thickness is 90 nm or less, the transparency of the paint can be maintained even when the content of the tin oxide fine particles is increased.
Therefore, if an optical material is produced using this tin oxide fine particle-dispersed coating material, an optical material that maintains transparency and has a high refractive index can be obtained easily and inexpensively.

  According to the method for producing an optical material of the present invention, the tin oxide fine particle-dispersed coating material of the present invention is cured, so that an optical material that maintains transparency and has a high refractive index can be obtained easily and inexpensively.

  According to the high refractive index film of the present invention, since it is formed using the optical material of the present invention, a high refractive index film maintaining transparency can be obtained easily and inexpensively.

  According to the antistatic film of the present invention, since it is formed using the optical material of the present invention, the transparency is maintained, the refractive index is increased, the conductivity is high, and the antistatic property is excellent in antistatic properties. A film can be obtained easily and inexpensively.

An optical material, a tin oxide fine particle dispersion, a tin oxide fine particle dispersion paint, an optical material manufacturing method, a high refractive index film, and an antistatic film will be described below.
The following embodiments are specifically described for better understanding of the gist of the invention, and do not limit the present invention unless otherwise specified.

[Optical materials]
The optical material of the present embodiment is an optical material obtained by dispersing tin oxide fine particles in a resin, and the dispersed particle diameter of the tin oxide fine particles is 10 nm or more and 90 nm or less, and the surface of the tin oxide fine particles is: The tin oxide fine particles are modified with a surface treatment material of 30% by mass or less.

Here, the reason for using tin oxide (SnO ₂ ) for the optical material of the present embodiment is that tin oxide itself has a high refractive index, so that an optical material having a high refractive index can be easily obtained, and tin oxide itself. Therefore, it is easy to impart conductivity and antistatic properties to the optical material, and it is cheaper than other high refractive index materials such as zirconium oxide and titanium oxide. .

The refractive index of tin oxide is about 2.00, which is sufficiently higher than the refractive index of about 1.3 to 1.5 of the resin itself. By dispersing tin oxide fine particles in the resin, a high refractive index is obtained. An optical material that is a composite can be obtained.
The refractive index of tin oxide is slightly lower than that of tetragonal zirconium oxide (refractive index of about 2.15) and titanium oxide (refractive index of about 2.5 (anatase) to about 2.7 (rutile)). In order to make the refractive index of the optical material using tin oxide equal to the refractive index of the optical material using zirconium oxide or titanium oxide, it is necessary to increase the content of tin oxide in the optical material. .

In the optical material of the present embodiment, the amount of the surface treatment material for treating the surface of the tin oxide fine particles is 30% by mass or less of the total amount of the tin oxide fine particles, whereby the tin oxide fine particles are contained in the optical material. The rate can be increased up to 80% by weight.
Moreover, since the dispersed particle diameter of the tin oxide fine particles is controlled to be 10 nm or more and 90 nm or less, the optical material does not lose transparency even when the content of the tin oxide fine particles is increased to 80% by mass.

  Furthermore, since tin oxide is cheaper than zirconium oxide and titanium oxide, even if the content of tin oxide fine particles in the optical material is increased, the optical material as a whole is optical using zirconium oxide or titanium oxide. Inexpensive compared to the material.

The range of the dispersed particle diameter of the tin oxide fine particles in the optical material of the present embodiment is preferably 10 nm or more and 90 nm or less, more preferably 10 nm or more and 50 nm or less.
Here, the reason why the dispersed particle diameter of the tin oxide fine particles is set to 90 nm or less is that the loss of transmitted light due to Rayleigh scattering can be suppressed by limiting the dispersed particle diameter to 90 nm or less.
In particular, Rayleigh scattering generated by particles having a dispersed particle diameter exceeding 90 nm is highly scattering. For example, when a film having a thickness of several tens of μm is formed using the optical material of the present embodiment, transmitted light due to Rayleigh scattering is reduced. Since loss cannot be ignored, it is not preferable.

In addition, the dispersion particle diameter is set to 10 nm or more because, when the dispersion particle diameter is less than 10 nm, the specific surface area of the tin oxide fine particles increases. Therefore, the necessary amount of the surface treatment agent for treating the surface of the tin oxide fine particles is remarkably increased. As a result, the refractive index of the oxide fine particles obtained by combining the tin oxide fine particles and the surface treatment agent is lowered, and it is difficult to obtain the effect of adding the oxide fine particles.
As will be described later, when the amount of the surface treatment agent is reduced or when the surface treatment agent is not used, the amount of the surface treatment agent used is not excessive even if the dispersed particle diameter is less than 10 nm. In this case, there is a possibility that the (re) aggregation of the tin oxide fine particles becomes remarkable during the production process of the optical material, and it is not preferable that the dispersed particle diameter is less than 10 nm.
Thus, if the dispersed particle diameter of the tin oxide fine particles is in the range of 10 nm or more and 90 nm or less, the amount of the surface treatment agent is controlled to 30% by mass or less with respect to the tin oxide fine particles. It is possible to obtain good affinity for the resin while suppressing the amount used.

In order to improve the affinity with the resin, the surface of the tin oxide fine particles is modified with a surface treatment agent of 30% by mass or less of the tin oxide fine particles.
The surface treatment agent is preferably an organosilicon compound, and examples of the organosilicon compound include a silicon-based coupling agent and silicone oil.

  Examples of the silicon coupling agent include methyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, methylmethoxysilane, n-propyltrimethoxysilane, n-butyltriethoxysilane, n-hexyltrimethoxysilane, n Silane coupling agents such as hexyltriethoxysilane, n-octyltriethoxysilane, n-decyltrimethoxysilane, phenyltrimethoxysilane, and diphenyldimethoxysilane; vinylsilane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane Aminosilane coupling agents such as 3-aminopropyltrimethoxysilane and N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane; 3-acryloxypropyltrimethoxysilane; Acryloxysilane coupling agents; methacryloxysilane coupling agents such as 3-methacryloxypropyltrimethoxysilane; mercaptosilane coupling agents such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltriethoxysilane .

Examples of the silicone oil include dimethyl silicone oil, methyl hydrogen silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, polyether-modified silicone oil, and amino-modified silicone oil.
These silicon coupling agents and silicone oils can be used alone or in combination of two or more.

  In particular, one or more kinds selected from the group of dimethyl silicone oil, methyl hydrogen silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, polyether-modified silicone oil, and amino-modified silicone oil are used as tin oxide fine particles. By using it as a surface treatment agent, the affinity with the resin is remarkably improved, and a highly transparent optical material can be obtained even if the amount used is suppressed to 30% by mass or less with respect to the mass of the tin oxide fine particles. .

  Here, the amount of the surface treatment agent used was 30% by mass or less of the tin oxide fine particles because the surface treatment agent having a lower refractive index than the tin oxide fine particles when the amount of the surface treatment agent used exceeded 30% by mass. As a result, the refractive index as a whole of the oxide fine particles obtained by combining the tin oxide and the surface treatment agent is lowered, and the function of the tin oxide fine particles as a high refractive index material is lowered. This is because it is not preferable.

When the antistatic property is imparted to the tin oxide fine particles, the amount of the surface treatment agent used is preferably 5% by mass or less of the tin oxide fine particles.
Here, when the amount of the surface treatment agent used is 5% by mass or less of the tin oxide fine particles, the affinity with the resin is reduced, but the probability that the tin oxide fine particles directly contact each other on the surface increases. As a result, an optical material using the tin oxide fine particles has conductivity, and an antistatic property can be imparted.

In order to make the tin oxide fine particles exhibit electrical conductivity and antistatic properties, the amount of the surface treatment agent used is preferably 1% by mass or less of the tin oxide fine particles.
However, when the amount of the surface treatment agent used is reduced, it is necessary to select a resin component capable of directly dispersing the tin oxide fine particles. The reason is that even when the amount of the surface treatment agent is reduced, the loss of transmitted light due to Rayleigh scattering is suppressed unless the dispersed particle diameter of the tin oxide fine particles in the optical material falls within the range of 10 nm to 90 nm. This is because the transparency of the optical material is lowered.

  The electrical conductivity and antistatic property depend not only on the amount of surface treatment agent used but also on the content of tin oxide fine particles, and the higher the content of tin oxide fine particles, the more conductive performance and antistatic performance are. improves. Therefore, in the optical material of the present embodiment, it is preferable to control the conductivity and antistatic property by combining the content of tin oxide fine particles and the amount of surface treatment agent used.

The resin used in the optical material of the present embodiment is transparent to light in a predetermined wavelength band such as visible light or near infrared, and the tin oxide fine particles in the resin are uniformly dispersed at a predetermined dispersed particle size. What is necessary is just resin to disperse, Curability, such as thermoplastic resin, thermosetting resin, light (electromagnetic wave) curable resin hardened | cured by visible light, ultraviolet rays, infrared rays, etc., electron beam curable resin hardened | cured by electron beam irradiation, etc. Resins are preferably used.
Examples of such curable resins include epoxy resins, silicone resins, acrylic resins, butyral resins, polyester resins, phenol resins, and melamine resins.

Here, when the tin oxide fine particles are surface-treated, it is preferable to use a silicone resin as the curable resin. The reason is that the silicone resin is excellent in heat resistance and light resistance, and also has high affinity with the surface treatment agent.
The silicone resin comprises a curable organopolysiloxane resin and a curing agent. Examples of the curable organopolysiloxane resin include dimethyl silicone resin, methylphenyl silicone resin, vinyl group-containing silicone resin, and amino group-containing silicone resin. , Methacryl group-containing silicone resin, carboxy group-containing silicone resin, epoxy group-containing silicone resin, carbinol group-containing silicone resin, phenyl group-containing silicone resin, organohydrogen silicone resin, alicyclic epoxy group-modified silicone resin, polycyclic Examples thereof include a hydrocarbon-containing silicone resin, an aromatic ring hydrocarbon-containing silicone resin, and a phenyl silsesquioxane resin.

  These silicone resins can be used alone or in combination of two or more. Moreover, as a hardening | curing agent, an aluminum compound, a platinum compound, a rhodium compound, a palladium compound etc. are mentioned as a hydrosilylation reaction catalyst. These can be used alone or in combination of two or more.

On the other hand, in order to impart conductivity and antistatic properties to the optical material of this embodiment, when the amount of the surface treatment agent with respect to the tin oxide fine particles is reduced, the tin oxide fine particles can be directly dispersed as the curable resin. It is necessary to select.
As such a curable resin, it is preferable to use a resin in which the resin before curing is soluble or dispersible in water which is a polar solvent. Typical examples of water-soluble resins include polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), but bisphenol resins, alkyd resins, urea / aldehyde resins, etc. also have water solubility. It is possible to select according to the required characteristics.

Examples of the water-dispersible resin include a water-dispersible urethane resin, an acrylic resin-based emulsion, and an aqueous two-component curable acrylic-urethane resin (aqueous polyol + water-dispersible polyisocyanate). Examples of the aqueous two-component curable acrylic-urethane resin include WE series and DNW series manufactured by Dainippon Ink and Chemicals.
In addition, even in such a resin that can be dissolved or dispersed in water, it has thermosetting property, light (electromagnetic wave) curable property, and electron beam curable property, so that it is water-soluble and water-dispersible after forming an optical material after curing. It is preferable not to show.

In the optical material of the present embodiment, the content of tin oxide fine particles is preferably 20% by mass or more and 80% by mass or less. The reason is that when the content is less than 20% by mass, the content of the tin oxide fine particles is too small, and it is difficult to obtain the effect of combining the tin oxide fine particles. .
On the other hand, if the content of the tin oxide fine particles exceeds 80% by mass, the content of the resin that fills the gaps between the tin oxide fine particles and bonds the tin oxide fine particles is too small. As a result, the optical material collapses. This is not preferable because it becomes easy to maintain the shape, or the transparency may be deteriorated.

The optical material of the present embodiment is different from the refractive index required for the target object depending on the type and specification of the object, and the refractive index of the resin itself varies depending on the type of resin used. Although the ratio to the resin cannot be uniformly defined, when this optical material is applied as a high refractive index film in a transparent film with an antistatic / antireflection film, the refractive index of the optical material is 1.6 to 1. It is preferable to adjust the kind of resin and the content of tin oxide fine particles so that it can be controlled within a range of about .7.
Thus, by defining the type of resin and the content of tin oxide fine particles, it is possible to obtain a transparent film having almost no interference unevenness, sufficient antireflection effect, and high antistatic properties.

  The maximum amount of the surface treatment agent used is 30% by mass of the tin oxide fine particles, whereas the maximum content of the tin oxide fine particles in the optical material is 80% by mass. In this combination, the resin amount is tin oxide. There is a possibility that the content of the resin becomes too small due to 4% by mass of the fine particles. Therefore, it is necessary to determine the contents of the three components of tin oxide fine particles, surface treatment agent, and resin in consideration of the properties of the surface treatment agent and resin to be used and the properties of the obtained optical material.

The optical material of this embodiment can be usefully used as an optical application due to its transparency and high refractive index characteristics. For example, when applied to a plastic lens, the thickness can be reduced or the focal length can be shortened in accordance with the high refractive index value, which makes the material useful for making optical products thinner and lighter.
In particular, since the optical material of the present embodiment has conductivity and antistatic properties, it can be suitably used as a transparent film with an antistatic / antireflection film applied to the display surface of an FPD.
Moreover, the shape of the optical material of the present embodiment can be appropriately selected depending on the application, such as a bulk shape, a film shape, or a sheet shape.

  According to the optical material of the present embodiment, an inexpensive tin oxide fine particle is selected as the high refractive index material, the dispersed particle diameter of the tin oxide fine particle is set to 10 nm or more and 90 nm or less, and the surface of the tin oxide fine particle is Since it was modified with a surface treatment agent of 30% by mass or less of the tin oxide fine particles, while suppressing the scattering of light by the tin oxide fine particles, particularly the scattering of light in the wavelength band of 350 nm to 800 nm in the visible light region, The content of tin oxide fine particles can be increased. Therefore, it is possible to obtain an optical material having a high refractive index while maintaining transparency at a low cost. Furthermore, since tin oxide has conductivity, it can also provide antistatic properties. .

[Tin oxide fine particle dispersion]
The tin oxide fine particle dispersion of the present embodiment is a tin oxide fine particle dispersion obtained by dispersing tin oxide fine particles in a dispersion medium, and the dispersed particle diameter of the tin oxide fine particles is 10 nm or more and 90 nm or less, The surface of the tin oxide fine particles is modified with a surface treatment material of 30% by mass or less of the tin oxide fine particles.

Here, the reason for using tin oxide (SnO ₂ ) in the dispersion liquid of the present embodiment is that the tin oxide itself has a high refractive index, and therefore, an optical material formed using the tin oxide fine particle dispersion liquid of the present embodiment. High refractive index properties can be easily imparted to tin oxide, and tin oxide itself has electrical conductivity. Therefore, it is possible to easily impart electrical conductivity and antistatic properties to optical materials, and in addition, zirconium oxide, which is another high refractive index material. And cheaper than titanium oxide.

The refractive index of tin oxide is about 2.00, which is sufficiently higher than the refractive index of the resin itself, which is about 1.3 to 1.5. An optical material formed using this tin oxide fine particle dispersion is Therefore, the refractive index can be easily increased.
The refractive index of tin oxide is slightly lower than that of tetragonal zirconium oxide (refractive index of about 2.15) and titanium oxide (refractive index of about 2.5 (anatase) to about 2.7 (rutile)). In order to make the refractive index of the optical material using tin oxide equal to the refractive index of the optical material using zirconium oxide or titanium oxide, it is necessary to increase the content of tin oxide in the optical material. .

In the tin oxide fine particle dispersion according to this embodiment, the amount of the surface treatment material for treating the surface of the tin oxide fine particles is set to 30% by mass or less of the total amount of the tin oxide fine particles, whereby the tin oxide fine particle dispersion The content of tin oxide fine particles in the optical material formed using can be increased to 80% by mass.
Further, since the dispersed particle diameter of the tin oxide fine particles is controlled to be 10 nm or more and 90 nm or less, the obtained optical material does not lose transparency even when the content of the tin oxide fine particles is increased to 80% by mass. .

  Furthermore, since tin oxide is cheaper than zirconium oxide or titanium oxide, the entire optical material can be obtained even if the content of tin oxide fine particles in the optical material formed using this tin oxide fine particle dispersion is increased. As compared with optical materials using zirconium oxide or titanium oxide, it is cheaper.

The range of the dispersed particle diameter of the tin oxide fine particles in the tin oxide fine particle dispersion of the present embodiment is preferably 10 nm or more and 90 nm or less, more preferably 10 nm or more and 50 nm or less.
Here, the reason why the range of the dispersed particle diameter is 10 nm or more and 90 nm or less is that the tin oxide fine particle dispersion and the uncured resin are mixed and dispersed in the optical material manufacturing method described later. This is because it is necessary to control the dispersed particle size of the inorganic fine particles in the optical material to 10 nm or more and 90 nm or less when the coating material of the form is obtained and the optical material of the present embodiment is obtained from the coating material.

That is, in the step of obtaining the tin oxide fine particle dispersion paint from the tin oxide fine particle dispersion of this embodiment, and further obtaining the optical material, it is unlikely that the tin oxide fine particles are crushed and the dispersed particle size is reduced. There is a possibility that the dispersed particle diameter is increased by aggregation of the tin oxide fine particles. Therefore, the maximum value of the dispersed particle diameter of the tin oxide fine particles in the dispersion must be at least equal to or less than the maximum value of the dispersed particle diameter of the tin oxide fine particles in the optical material. Therefore, the upper limit of the dispersed particle diameter of the tin oxide fine particles was set to 90 nm.
Another reason for setting the upper limit of the dispersed particle diameter to 90 nm is to suppress the loss of transmitted light due to Rayleigh scattering of the optical material obtained from the tin oxide fine particle dispersion of this embodiment, as already described. .
Since the dispersion particle diameter of the tin oxide fine particles in the tin oxide fine particle dispersion of this embodiment is 90 nm or less, the transparency of the dispersion itself can be maintained even if the content of the tin oxide fine particles is increased.

  In addition, since the surface treatment performed to increase the affinity between the tin oxide fine particles and the resin is performed in the state of the tin oxide fine particles alone or in the state of the dispersion, the dispersed particle diameter is 10 nm in the state of the dispersion. If it is less than 1, the increase in the specific surface area of the tin oxide fine particles and the increase in the necessary amount of the surface treatment agent accompanying this increase will be significant. Even if the tin oxide fine particles subjected to surface treatment are aggregated to increase the dispersed particle size of the tin oxide fine particles, the amount of the surface treatment agent already bonded to the surface of the tin oxide fine particles is not reduced. Therefore, when the dispersed particle diameter of the tin oxide fine particles in the dispersion is less than 10 nm, the surface treatment for the tin oxide fine particles is performed regardless of the dispersed particle diameter of the tin oxide fine particles in the optical material obtained using this dispersion. The amount of the agent used is excessive, and as a result, the refractive index of the entire fine particles of the tin oxide fine particles and the surface treatment agent is lowered, and it is difficult to obtain the effect of adding the tin oxide fine particles.

On the other hand, when the amount of the surface treatment agent used is reduced, the amount of the surface treatment agent used does not become excessive even if the dispersed particle diameter is less than 10 nm. Therefore, it is not preferable that the dispersed particle size is less than 10 nm.
As described above, when the dispersed particle diameter is in the range of 10 nm or more and 90 nm or less, the amount of the surface treatment agent is controlled by controlling the amount of the surface treatment agent to 30% by mass or less with respect to the tin oxide fine particles. It becomes possible to give good characteristics to the optical material formed using this tin oxide fine particle dispersion.

In order to improve the affinity with the resin, the surface of the tin oxide fine particles is modified with a surface treatment agent of 30% by mass or less of the tin oxide fine particles.
The surface treatment agent is preferably an organosilicon compound, and examples of the organosilicon compound include a silicon-based coupling agent and silicone oil. In addition, since the kind of surface treating agent has already been described, the details are omitted.

  Here, the amount of the surface treatment agent used is 30% by mass or less, when the amount of the surface treatment agent used exceeds 30% by mass, the relative amount of the surface treatment agent having a refractive index lower than that of the tin oxide fine particles. This increases the refractive index of the entire fine particle combining the tin oxide fine particles and the surface treatment agent, and the effect of adding the high refractive index tin oxide fine particles is lost.

Moreover, when the amount of the surface treatment agent used is 5% by mass or less of the tin oxide fine particles, the probability that the surfaces of the tin oxide fine particles are in direct contact with each other when the optical material is formed using this tin oxide fine particle dispersion. Since the conductive path is formed by the tin oxide fine particles in the optical material, it becomes possible for the optical material to have conductivity and to impart antistatic properties.
In order to develop conductivity and antistatic property, the amount of the surface treatment agent used is preferably 1% by mass or less of the tin oxide fine particles.

  In addition, when the usage-amount of a surface treating agent is reduced in this way, it is necessary to select what can disperse | distribute a tin oxide fine particle directly as a dispersion medium. That is, even when the amount of the surface treatment agent is reduced, the dispersion particle diameter of the tin oxide fine particles in the dispersion must be within the range of 10 nm or more and 90 nm or less, and aggregation of the tin oxide fine particles must be prevented. This is because loss of transmitted light due to Rayleigh scattering of tin oxide fine particles in the optical material formed using this dispersion cannot be suppressed, and the transparency of the optical material is lowered.

  As a dispersion medium, tin oxide fine particles can be dispersed. In the manufacturing method of tin oxide fine particle-dispersed paint and optical material described later, this dispersion is dispersed and mixed in an uncured resin to form a paint. In doing so, it is necessary to select one that is highly compatible with the uncured resin.

  Here, in order to improve the affinity between the tin oxide fine particles and the resin, the surface of the tin oxide fine particles is modified with a surface treatment agent of 30% by mass or less of the tin oxide fine particles, and is uncured. When an epoxy resin, a silicone resin, an acrylic resin, a butyral resin, a polyester resin, a phenol resin, a melamine resin or the like is selected as the resin, as a dispersion medium having high compatibility with such an uncured resin, for example, , Alcohols such as methanol, ethanol, 2-propanol, butanol, octanol, ethyl acetate, butyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, esters such as γ-butyrolactone, diethyl ether, Ethylene glycol mono Ethers such as chill ether (methyl cellosolve), ethylene glycol monoethyl ether (ethyl cellosolve), ethylene glycol monobutyl ether (butyl cellosolve), diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, acetylacetone, Examples include ketones such as cyclohexanone, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene, and amides such as dimethylformamide, N, N-dimethylacetoacetamide, and N-methylpyrrolidone. Among these dispersion media, 1 Only a seed | species or 2 or more types can be mixed and used.

In addition, when the amount of the tin oxide fine particle surface treatment agent used is reduced, that is, when an uncured resin that can disperse the tin oxide fine particles directly is selected, the phase is compared with the uncured resin. An example of a highly soluble dispersion medium is water. The reason is that the tin oxide fine particles with a reduced amount of the surface treatment agent are dispersed only in the polar dispersion medium, and therefore it is necessary to select a resin that can be dissolved or dispersed in water.
Examples of the uncured resin include an aqueous resin solution or an aqueous dispersion (emulsion).

  Examples of the polar dispersion medium include water, lower alcohols such as methanol, ethanol and 2-propanol, lower ketones such as acetone and methyl ethyl ketone (MEK), and the like. However, when mixed with water, the solubility and dispersibility of water may be significantly reduced, so care must be taken.

The content of tin oxide fine particles in the dispersion is preferably 1% by mass to 80% by mass, more preferably 10% by mass to 70% by mass.
When the content of the tin oxide fine particles is less than 1% by mass, the amount of addition and use is large when the dispersion is used, including the case where the optical material of this embodiment is obtained using this dispersion. This is because the handling properties are deteriorated, or troubles such as time and effort are required to remove the dispersion medium.
Further, if the content exceeds 80% by mass, the dispersion stability of the dispersion is deteriorated, the aggregation of tin oxide fine particles is likely to occur, and there is a risk that the dispersion particle diameter exceeds 90 nm. It is not preferable.

  In addition, in the tin oxide fine particle dispersion of this embodiment, other substances such as a dispersant, a dispersion aid, a coupling agent, and the like may be added as long as the characteristics and the object of the present invention are not impaired.

  According to the tin oxide fine particle dispersion of the present embodiment, inexpensive tin oxide fine particles are selected as the high refractive index material, and the dispersed particle diameter of the tin oxide fine particles is set to 10 nm or more and 90 nm or less. Is modified with a surface treatment material of 20% by mass or less of the tin oxide fine particles, so that the transparency of the dispersion can be maintained even if the content of the tin oxide fine particles is increased. Therefore, by producing a tin oxide fine particle dispersed paint using this tin oxide fine particle dispersion, it is possible to easily and inexpensively obtain a tin oxide fine particle dispersed paint having a high content of tin oxide fine particles and maintaining transparency. it can.

[Tin oxide fine particle dispersion paint]
The tin oxide fine particle paint of the present embodiment is a tin oxide fine particle dispersed paint obtained by dispersing and mixing the tin oxide fine particle dispersion of the present embodiment and an uncured resin, and the oxidation in the tin oxide fine particle dispersed paint is performed. The dispersed particle diameter of the tin fine particles is 10 nm or more and 90 nm or less.

Here, the uncured resin is an uncured state of the resin used in the optical material of the present embodiment, and its state is an uncured liquid like a resin monomer or oligomer. Not only a certain thing but what dissolved resin in the solvent with high compatibility with the dispersion medium in the tin oxide fine particle dispersion of this embodiment may be used.
Further, it may be soluble in the dispersion medium of the tin oxide fine particle dispersion and be in a dissolved state by being dispersed and mixed with the tin oxide fine particle dispersion.
Further, a so-called emulsion state in which a resin is dispersed in a solvent having high compatibility with the dispersion medium in the tin oxide fine particle dispersion of this embodiment described above may be used.

  The type of such resin is described in the optical material of the present embodiment described above, and details thereof are omitted. For example, epoxy resin, silicone resin, acrylic resin, butyral resin, polyester resin, phenol resin, Examples thereof include curable resins such as melamine resins, water-soluble resins such as polyvinyl alcohol and polyvinylpyrrolidone, water-dispersible resins such as water-dispersed urethane resins and acrylic resin emulsions.

  In addition, the reason why the range of the dispersed particle diameter of the tin oxide fine particles in this tin oxide fine particle-dispersed coating material is 10 nm or more and 90 nm or less is that when the optical material is obtained from the paint of the present embodiment by the optical material manufacturing method described later. This is because it is necessary to control the dispersed particle size of the inorganic fine particles in the optical material to be 10 nm or more and 90 nm or less.

  The reason for controlling the dispersed particle size to 90 nm or less in this tin oxide fine particle-dispersed coating is the same as that of the tin oxide fine particle dispersion of the present embodiment described above, and in the step of obtaining an optical material from the tin oxide fine particle paint of the present embodiment. However, it is unlikely that the tin oxide fine particles will be crushed and the dispersed particle size will decrease, while the dispersed particle size may increase due to aggregation. The maximum value of the dispersed particle diameter must be at least equal to or less than the maximum value of the dispersed particle diameter in the tin oxide fine particles in the optical material.

Another reason for controlling the dispersed particle size to 90 nm or less is that, as described in the optical material of the present embodiment, the Rayleigh scattering is also applied to the optical material obtained from the tin oxide fine particle paint of the present embodiment. This is because it is necessary to suppress the loss of transmitted light due to.
In addition, since the dispersed particle diameter of the tin oxide fine particles is 90 nm or less, even in the tin oxide fine particle dispersed paint of this embodiment, the transparency of the paint itself can be maintained even if the content of the tin oxide fine particles is increased. .

The reason for controlling the dispersed particle size to 10 nm or more is that, as in the optical material of the present embodiment described above, when the dispersed particle size is less than 10 nm, the specific surface area of the fine particles increases, thereby increasing the affinity with the resin. Therefore, the necessary amount of the surface treatment agent to be applied is remarkably increased. As a result, the refractive index of the entire fine particles of the tin oxide fine particles and the surface treatment agent is lowered, and the effect of adding the tin oxide fine particles is obtained. Because it becomes difficult.
Furthermore, when the amount of the surface treatment agent used is reduced, the (re) aggregation of the tin oxide fine particles may become significant during the manufacturing process of the optical material. It is not preferable.

  According to the tin oxide fine particle-dispersed paint of the present embodiment, the tin oxide fine particle-dispersed paint is obtained by dispersing and mixing the tin oxide fine particle dispersion of the present embodiment and an uncured resin. Since the dispersed particle diameter of the tin oxide fine particles is 10 nm or more and 90 nm or less, the transparency of the paint can be maintained even if the content of the tin oxide fine particles is increased. Therefore, if an optical material is produced using this tin oxide fine particle-dispersed coating material, an optical material that maintains transparency and has a high refractive index can be obtained easily and inexpensively.

[Production method of optical material]
The manufacturing method of the optical material of this embodiment is a method of curing the tin oxide fine particle dispersed paint of this embodiment.
That is, the tin oxide fine particle dispersion of this embodiment and an uncured resin are dispersed and mixed to form the tin oxide fine particle dispersed paint of this embodiment, and then this paint is cured.
Hereinafter, the manufacturing method of this optical material will be described in detail.

First, tin oxide fine particles and a dispersion medium are mixed, and a surface treatment agent is added as necessary, followed by dispersion treatment to produce a tin oxide fine particle dispersion of this embodiment. The surface treatment of the tin oxide fine particles may be performed in advance before the dispersion medium is charged.
Here, as the mixing and dispersing methods, in addition to various mills, existing methods such as application of ultrasonic waves can be used.

Next, the obtained tin oxide fine particle dispersion of this embodiment and the uncured resin are mixed, and the tin oxide fine particles are uniformly dispersed in the uncured resin to produce the tin oxide fine particle dispersed paint of this embodiment. .
Here, since the tin oxide fine particles cannot be uniformly dispersed in the resin when the dispersion is not uniformly mixed in the uncured resin, the dispersion medium used for the dispersion is an uncured resin. It is preferable to select a material having high compatibility with respect to.
The mixing ratio between the tin oxide fine particle dispersion and the uncured resin depends on the refractive index and conductivity (antistatic properties) of the target optical material, the content of the tin oxide fine particles in the dispersion, and the refraction of the resin used. In general, the content of the tin oxide fine particles in the optical material is about 40% by weight or more in order to make the refractive index of the obtained optical material 1.6 or more. It is preferable.

Here, when an uncured resin such as a resin monomer or oligomer that is in an uncured liquid state is selected, a mixture of the tin oxide fine particle dispersion and the uncured resin is used. The dispersion medium contained in the dispersion is removed by evaporation or the like to form a tin oxide fine particle-dispersed paint.
Evaporation of the dispersion medium may be carried out by simply allowing the mixture to stand, but agglomeration of the inorganic fine particles can be prevented by kneading the inorganic fine particles and the uncured resin. It is preferable because evaporation of the medium can be promoted.
It should be noted that if the dispersion medium is rapidly evaporated, the generated dispersion medium vapor becomes bubbles in the resin, which reduces the transparency of the optical material.
In addition, when the viscosity of the uncured resin is high or the content of the tin oxide fine particles is high, the viscosity of the prepared paint is high, and if there is a problem in handling, leave the dispersion medium without evaporating, Alternatively, a viscosity adjusting solvent may be newly added.

  On the other hand, as an uncured resin, (1) a resin dissolved in a solvent, (2) soluble in a dispersion medium of a tin oxide fine particle dispersion, and dissolved by mixing with a tin oxide fine particle dispersion (3) In the case where an emulsion in which a resin is dispersed in a solvent having high compatibility with the dispersion medium in the tin oxide fine particle dispersion of the present embodiment is selected, the tin oxide fine particle dispersion If the dispersion medium and the resin solvent contained in the dispersion are completely removed from the mixture of the uncured resin and the uncured resin, the prepared coating itself may lose its viscosity. In this case, it is necessary to add a solvent for adjusting the viscosity before the dispersion medium and the solvent are completely removed without being completely removed, or before the paint itself loses its viscosity.

  Next, the obtained tin oxide fine particle-dispersed paint of this embodiment is molded into a required shape to obtain a molded body. As a molding method, a method of pouring a paint into a mold may be used, or a bulk body may be formed in advance, and a desired shape may be cut out from the bulk body. In addition, if the molded body is a film, a method of forming a coating film on the substrate using, for example, a spray coating method, a bar coating method, a doctor blade method, a spin coating method, or the like may be used. These molding methods can use existing methods.

Next, the uncured resin contained in the molded body is cured to obtain an optical material.
Here, when the molded body contains a dispersion medium or a solvent, the contained dispersion medium or solvent is volatilized and removed by heating the molded body in advance.
What is necessary is just to select suitably as a method of hardening according to resin to be used.
For example, in the case of a thermosetting resin, it may be heated at a predetermined temperature for a predetermined time using a heating furnace or the like. In the case of a light (electromagnetic wave) curable resin, visible light, ultraviolet light, infrared light, or the like may be irradiated for a predetermined time at a predetermined intensity. Moreover, if it is an electron beam curable resin, what is necessary is just to irradiate an electron beam with predetermined intensity | strength for predetermined time. Further, in the case of a thermoplastic resin, the resin that has been softened by heating in advance and the inorganic fine particle dispersion described above are mixed, and after the dispersion medium in the dispersion is removed, cooling and curing may be performed.
In any case, rapid curing is not preferable because it causes a decrease in transparency.

  According to the method for producing an optical material of the present embodiment, the tin oxide fine particle-dispersed coating material of the present embodiment is cured, so that an optical material that maintains transparency and has a high refractive index can be obtained easily and inexpensively. .

[High refractive index film]
The high refractive index film of the present embodiment is formed using the optical material of the present embodiment, and is formed in a film shape on a substrate.

The substrate may be a substrate having transparency with respect to light of a predetermined wavelength band such as visible light or near infrared, and is selected from a glass substrate and various transparent resins according to the purpose. .
Here, examples of the resin for the substrate include polyacrylates such as polymethyl methacrylate (PMMA) and polycyclohexyl methacrylate, polycarbonate (PC), polyethylene terephthalate (PET), polystyrene (PS), and polyester.

In particular, when the high refractive index film of the present embodiment is used as a transparent film with an antistatic / antireflection film applied to an FPD image display unit or the like, the mechanical strength, flexibility, etc. , Impact resistance, light weight, etc. are required. Polyethylene terephthalate (PET) or polycarbonate (PC) is preferably used as the resin for such applications.
Further, the shape may be any of a flat plate, a film, a sheet and the like, and is selected according to the purpose.
Furthermore, the surface of the substrate may be subjected to a surface treatment for improving the adhesion with the high refractive index film to be formed.

The high refractive index film of this embodiment is a film of the optical material of this embodiment as described above, and the film thickness is determined by the refractive index of the film and the required optical and physical characteristics (film Strength, scratch resistance, etc.). For example, if the film functions simply as a high-refractive index film, the thickness may be about 0.1 μm. On the other hand, when film strength is required, such as when used for a touch panel, a film thickness of 10 μm or more is required. In some cases.
The high refractive index film of the present embodiment is highly transparent because the optical material of the present embodiment is used, and even if the film thickness is 10 μm or more, the transparency does not decrease and a good high refractive index film is obtained. Obtainable.

  Further, the high refractive index film of this embodiment is not only used alone, but may be used in combination with other functional films. For example, an antireflection film can be formed by combining the high refractive index film of this embodiment with a low refractive index film. This antireflection film can be suitably used for FPD.

The high refractive index film of the present embodiment can be produced according to the optical material production method of the present embodiment, using the base material and the tin oxide fine particle-dispersed coating material of the present embodiment.
Here, an outline of this manufacturing method will be described.
First, the tin oxide fine particle-dispersed coating material of the present embodiment is applied on a transparent substrate to form a coating film.
The coating method is not particularly limited. For example, a roll coating method such as a gravure coating method, a spin coating method, a dip coating method, a spray coating method, a slide coating method, a bar coating method, a meniscus coater method, flexographic printing. Various coating methods such as a coating method, a screen printing method, and a bead coater method are used.

Next, the coating film is heat-dried or naturally dried to volatilize and remove the dispersion medium and solvent contained in the coating film, and then the resin is cured using a curing method suitable for the resin used in the paint. Let
For example, in the case of a thermosetting resin, it may be heated at a predetermined temperature for a predetermined time using a heating furnace or an electric furnace, and in the case of a light (electromagnetic wave) curable resin, visible light, ultraviolet light or infrared light is used. May be irradiated at a predetermined intensity for a predetermined time, and if it is an electron beam curable resin, an electron beam may be irradiated at a predetermined intensity for a predetermined time.
Further, in the case of a thermoplastic resin, the resin that has been softened by heating in advance and the inorganic fine particle dispersion described above are mixed, and after the dispersion medium in the dispersion is removed, cooling and curing may be performed.
In this way, the high refractive index film of this embodiment can be produced.

  According to the high refractive index film of the present embodiment, since the optical material of the present embodiment is used to form a film, a high refractive index film that maintains transparency can be obtained easily and inexpensively.

[Antistatic film]
The antistatic film of the present embodiment has a probability that the surfaces of the tin oxide fine particles are in direct contact with each other by setting the amount of the surface treatment agent used in the optical material of the present embodiment to 5% by mass or less of the tin oxide fine particles. An optical material having a conductive path formed of tin oxide fine particles formed in an optical material is formed on a substrate in the form of a film.

Here, the base material to be used, the shape and thickness of the antistatic film, and the formation method of the antistatic film are the same as those of the above-described high refractive index film, and thus description thereof is omitted.
In addition, in the antistatic film of this embodiment, it is necessary to increase the content of tin oxide fine particles in order to form a conductive path by the tin oxide fine particles. Therefore, this antistatic film usually has a high refractive index. It also has a “high refractive index / antistatic film”. Therefore, by combining the antistatic film of this embodiment with a low refractive index film, an antistatic / antireflection film having both an antistatic function and an antireflection function can be formed. It can be suitably used for FPD.

  According to the antistatic film of the present embodiment, the optical material of the present embodiment is used, and the conductive path is formed by the tin oxide fine particles in the optical material. Therefore, transparency is maintained and the refractive index is increased. An antistatic film having conductivity and excellent antistatic properties can be obtained easily and inexpensively.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

[Example 1]
"Preparation and evaluation of tin oxide dispersion"
30 g of tin oxide fine particles (Sumitomo Osaka Cement, primary particle size 10-15 nm), 67 g of methyl ethyl ketone as a dispersion medium, 3 g of silane coupling agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a surface treatment agent (total amount of tin oxide fine particles) Then, a dispersion treatment was performed at 3000 rpm for 5 hours using a bead mill using 150 g of glass beads. Thereafter, the glass beads were separated by filter treatment to obtain a tin oxide fine particle dispersion SM10.
As a result of measuring the dispersed particle size of the tin oxide fine particles in this tin oxide fine particle dispersion SM10 using a dynamic light scattering type particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 10 nm to 120 nm. there were.

Next, the tin oxide fine particle dispersion SM10 was subjected to ultrasonic dispersion treatment to obtain a tin oxide fine particle dispersion SM10R.
As a result of measuring the dispersed particle size of the tin oxide fine particles in the obtained tin oxide fine particle dispersion SM10R using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 10 nm to 90 nm. It was in.
Further, the haze value of the tin oxide fine particle dispersion SM10R was measured using a spectrophotometer (manufactured by Nippon Denshoku). The sample was placed in a glass cell having an optical path length of 10 mm and a width of 20 mm, and as a result, the haze value was 6.

"Preparation of tin oxide fine particle dispersion paint"
20 g of the tin oxide fine particle dispersion SM10R was weighed, 21.9 g of a hexafunctional acrylic ultraviolet curable resin DPHA (manufactured by Nippon Kayaku Co., Ltd.) as an uncured resin, and Irgacure 184 (manufactured by Ciba Specialty) as a photoinitiator 1 0.5 g (7% by mass with respect to the resin) was added, and 56.6 g of diacetone alcohol was further added to make the total amount 100 g, and then dispersed and mixed to obtain a tin oxide fine particle dispersed paint SM10RP.

This tin oxide fine particle-dispersed coating SM10RP had a solid content of 30% by mass, and the ratio of tin oxide fine particles in the solid content was 20% by mass.
Moreover, as a result of measuring the dispersed particle diameter of the tin oxide fine particles in the tin oxide fine particle dispersed paint SM10RP using a dynamic light scattering type particle size distribution measuring apparatus (manufactured by Malvern), the dispersed particle diameter is in the range of 10 nm to 90 nm. Met.

"Preparation of high refractive index film"
A polyethylene terephthalate (PET) film T600E-50N (manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material for film formation, and a tin oxide fine particle dispersion paint SM10RP is applied onto the base material using a bar coating method. A coating film was formed to obtain a substrate with a coating film. The thickness of the coating film was adjusted so that the film thickness after curing was 10 μm.
Subsequently, this base material with a coating film was conveyed to a hot-air drying furnace, dried at 100 ° C. for 3 minutes, and then cured by irradiation with ultraviolet rays (integrated light amount 700 mJ / cm ² ). The high refractive index film of Example 1 SM10RF was obtained.

[Example 2]
"Preparation and evaluation of tin oxide dispersion"
30 g of tin oxide fine particles (manufactured by Sumitomo Osaka Cement, primary particle size 10-15 nm), 61 g of methyl ethyl ketone as a dispersion medium, and 9 g of silane coupling agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a surface treatment agent (total amount of tin oxide fine particles) 30% by mass), and then a dispersion treatment was performed at 3000 rpm for 5 hours using a bead mill using 150 g of glass beads. Thereafter, the glass beads were separated by filtering to obtain a tin oxide fine particle dispersion SM30.
As a result of measuring the dispersed particle size of the tin oxide fine particles in this tin oxide fine particle dispersion SM30 using a dynamic light scattering type particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 20 nm to 120 nm. there were.

Next, the tin oxide fine particle dispersion SM30 was subjected to ultrasonic dispersion treatment to obtain a tin oxide fine particle dispersion SM30R.
As a result of measuring the dispersed particle size of the tin oxide fine particles in the obtained tin oxide fine particle dispersion SM30R using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 10 nm to 90 nm. It was in.
Further, the haze value of the tin oxide fine particle dispersion SM20R was measured using a spectrophotometer (manufactured by Nippon Denshoku). The sample was placed in a glass cell having an optical path length of 10 mm and a width of 20 mm, and as a result, the haze value was 10.

"Preparation of tin oxide fine particle dispersion paint"
80 g of the tin oxide fine particle dispersion SM30R was weighed, and 3.4 g of a hexafunctional acrylic UV curable resin DPHA (manufactured by Nippon Kayaku Co., Ltd.) as an uncured resin, and Irgacure 184 (manufactured by Ciba Specialty) as a photoinitiator 0 0.2 g (7% by mass with respect to the resin) was added, and 16.4 g of diacetone alcohol was further added to make the total amount 100 g, and then dispersed and mixed to obtain a tin oxide fine particle dispersed coating SM30RP.

This tin oxide fine particle-dispersed coating SM30RP had a solid content of 30% by mass, and the ratio of tin oxide fine particles in the solid content was 80% by mass.
Moreover, as a result of measuring the dispersed particle diameter of the tin oxide fine particles in the tin oxide fine particle dispersed paint SM20RP using a dynamic light scattering type particle size distribution measuring apparatus (manufactured by Malvern), the dispersed particle diameter is in the range of 10 nm to 90 nm. Met.

"Preparation of high refractive index film"
A polyethylene terephthalate (PET) film T600E-50N (manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material for film formation, and a tin oxide fine particle dispersed paint SM30RP is applied onto the base material using a bar coating method. A coating film was formed to obtain a substrate with a coating film. The thickness of the coating film was adjusted so that the film thickness after curing was 10 μm.
Subsequently, this base material with a coating film was conveyed to a hot air drying oven, dried at 100 ° C. for 3 minutes, and then cured by irradiation with ultraviolet rays (integrated light amount 700 mJ / cm ² ). The high refractive index film of Example 2 SM30RF was obtained.

[Example 3]
"Preparation and evaluation of tin oxide dispersion"
After mixing 30 g of tin oxide fine particles (manufactured by Sumitomo Osaka Cement, primary particle size 10-15 nm) with 70 g of ammonia water (NH ₃ : 0.1 mol / L) as a dispersion medium, a bead mill using 150 g of glass beads is used. Then, the dispersion treatment was performed at 3000 rpm for 5 hours. Thereafter, the glass beads were separated by filter treatment to obtain a tin oxide fine particle dispersion SW1.
As a result of measuring the dispersed particle size of the tin oxide fine particles in this tin oxide fine particle dispersion SW1 using a dynamic light scattering type particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 20 nm to 120 nm. there were. In this tin oxide fine particle dispersion SW1, no surface treatment agent is used.

Next, the tin oxide fine particle dispersion SW1R was subjected to ultrasonic dispersion treatment to obtain a tin oxide fine particle dispersion SW1R.
As a result of measuring the dispersed particle size of the tin oxide fine particles in the obtained tin oxide fine particle dispersion SW1R using a dynamic light scattering type particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 10 nm to 90 nm. It was in.
Further, the haze value of the tin oxide fine particle dispersion SW1R was measured using a spectrophotometer (manufactured by Nippon Denshoku). The sample was placed in a glass cell having an optical path length of 10 mm and a width of 20 mm, and as a result, the haze value was 8.

"Preparation of tin oxide fine particle dispersion paint"
50 g of tin oxide fine particle dispersion SW1R was weighed, and 30.3 g of acrylic emulsion WE-308 (manufactured by Dainippon Ink & Chemicals (DIC)) as an uncured resin, and polyisocyanate DNW5000 (manufactured by DIC) 1 as a curing agent 0.4 g (10% by mass with respect to the resin) was added, and further 18.3 g of water was added to make the total amount 100 g, and then dispersed and mixed to obtain a tin oxide fine particle dispersed paint SW1RP.

The tin oxide fine particle dispersed paint SW1RP had a solid content of 30% by mass, and the ratio of the tin oxide fine particles in the solid content was 50% by mass.
In addition, as a result of measuring the dispersed particle size of the tin oxide fine particles in the tin oxide fine particle dispersed paint SW1RP using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 10 nm to 90 nm. Met.

"Preparation of high refractive index film"
A polyethylene terephthalate (PET) film T600E-50N (manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material for film formation, and a tin oxide fine particle dispersed paint SW1RP is applied onto the base material using a bar coating method. A coating film was formed to obtain a substrate with a coating film. The thickness of the coating film was adjusted so that the film thickness after curing was 10 μm.
Subsequently, this base material with a coating film was conveyed to a hot-air drying furnace and cured by heat treatment at 100 ° C. for 3 minutes to obtain a high refractive index film SW1RF of Example 3.

[Example 4]
"Preparation and evaluation of tin oxide dispersion"
In the same manner as in Example 1, a tin oxide fine particle dispersion SM10R was obtained.
As a result of measuring the dispersed particle size of the tin oxide fine particle dispersion SM10R using a dynamic light scattering particle size distribution measuring apparatus (manufactured by Malvern), the dispersed particle size was in the range of 10 nm to 90 nm.
Moreover, as a result of measuring the haze value of the tin oxide fine particle dispersion SM10R using a spectrophotometer (manufactured by Nippon Denshoku), the haze value was 6.

"Preparation of tin oxide fine particle dispersion paint"
10 g of this tin oxide fine particle dispersion SM10R was weighed, 25 g of a hexafunctional acrylic UV curable resin DPHA (manufactured by Nippon Kayaku Co., Ltd.) as an uncured resin, and Irgacure 184 (manufactured by Ciba Specialty) as a photoinitiator. 7 g (7% by mass with respect to the resin) was added, and 63.3 g of diacetone alcohol was added to make the total amount 100 g, and then dispersed and mixed to obtain a tin oxide fine particle dispersed paint SM10RP2.

This tin oxide fine particle-dispersed coating SM10RP2 had a solid content of 30% by mass, and the ratio of the tin oxide fine particles in the solid content was 10% by mass.
In addition, as a result of measuring the dispersed particle size of the tin oxide fine particles in the tin oxide fine particle dispersed coating SM10RP2 using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 10 nm to 90 nm. Met.

"Preparation of high refractive index film"
A polyethylene terephthalate (PET) film T600E-50N (manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material for film formation, and a tin oxide fine particle dispersion paint SM10RP2 is applied onto the base material using a bar coating method. A coating film was formed to obtain a substrate with a coating film. The thickness of the coating film was adjusted so that the film thickness after curing was 10 μm.
Subsequently, this base material with a coating film was conveyed to a hot-air drying oven, dried at 100 ° C. for 3 minutes, and then cured by irradiation with ultraviolet rays (integrated light amount 700 mJ / cm ² ). The high refractive index film of Example 4 SM10RF2 was obtained.

[Example 5]
"Preparation and evaluation of tin oxide dispersion"
In the same manner as in Example 1, a tin oxide fine particle dispersion SM10R was obtained.
As a result of measuring the dispersed particle size of the tin oxide fine particle dispersion SM10R using a dynamic light scattering particle size distribution measuring apparatus (manufactured by Malvern), the dispersed particle size was in the range of 10 nm to 90 nm.
Moreover, as a result of measuring the haze value of the tin oxide fine particle dispersion SM10R using a spectrophotometer (manufactured by Nippon Denshoku), the haze value was 6.

"Preparation of tin oxide fine particle dispersion paint"
90 g of this tin oxide fine particle dispersion SM10R was weighed, 0.009 g of a hexafunctional acrylic UV curable resin DPHA (manufactured by Nippon Kayaku Co., Ltd.) as an uncured resin, and Irgacure 184 (manufactured by Ciba Specialty) as a photoinitiator. 0.001 g (7% by mass with respect to the resin) was added, and further 9.9 g of diacetone alcohol was added to make the total amount 100 g, and then dispersed and mixed to obtain a tin oxide fine particle dispersed paint SM10RP3.

This tin oxide fine particle-dispersed coating SM10RP3 had a solid content of 30% by mass, and the ratio of the tin oxide fine particles in the solid content was 90% by mass.
In addition, as a result of measuring the dispersed particle diameter of the tin oxide fine particles in the tin oxide fine particle dispersed paint SM10RP3 using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), the dispersed particle diameter is in the range of 10 nm to 90 nm. Met.

"Preparation of high refractive index film"
A polyethylene terephthalate (PET) film T600E-50N (manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material for film formation, and a tin oxide fine particle dispersion paint SM10RP3 is applied onto the base material using a bar coating method. A coating film was formed to obtain a substrate with a coating film. The thickness of the coating film was adjusted so that the film thickness after curing was 10 μm.
Subsequently, this base material with a coating film was conveyed to a hot-air drying furnace, dried at 100 ° C. for 3 minutes, and then cured by irradiation with ultraviolet rays (integrated light amount 700 mJ / cm ² ). The high refractive index film of Example 5 SM10RF3 was obtained.

[Comparative Example 1]
"Preparation and evaluation of tin oxide dispersion"
30 g of tin oxide fine particles (manufactured by Sumitomo Osaka Cement, primary particle size 90-100 nm), 64 g of methyl ethyl ketone as a dispersion medium, 6 g of silane coupling agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a surface treatment agent (total amount of tin oxide fine particles) 20 mass%) was mixed, and then a dispersion treatment was performed at 3000 rpm for 5 hours using a bead mill using 150 g of glass beads. Thereafter, the glass beads were separated by filtering to obtain a tin oxide fine particle dispersion SM20B.
As a result of measuring the dispersed particle size of the tin oxide fine particles in this tin oxide fine particle dispersion SM20B using a dynamic light scattering type particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 20 nm to 120 nm. there were.
Further, the haze value of the tin oxide fine particle dispersion SM20B was measured using a spectrophotometer (manufactured by Nippon Denshoku). The sample was placed in a glass cell having an optical path length of 10 mm and a width of 20 mm, and as a result, the haze value was 30.

"Preparation of tin oxide fine particle dispersion paint"
20 g of this tin oxide fine particle dispersion SM20B is weighed, 21.9 g of hexafunctional acrylic UV curable resin DPHA (manufactured by Nippon Kayaku Co.) as an uncured resin, and Irgacure 184 (manufactured by Ciba Specialty) as a photoinitiator. 1.5 g (7% by mass with respect to the resin) was added, and 56.6 g of diacetone alcohol was further added to make the total amount 100 g, and then dispersed and mixed to obtain a tin oxide fine particle dispersed paint SM20BP.

This tin oxide fine particle-dispersed coating SM20BP had a solid content of 30% by mass, and the ratio of tin oxide fine particles in the solid content was 20% by mass.
In addition, as a result of measuring the dispersed particle size of the tin oxide fine particles in the tin oxide fine particle dispersed coating SM20BP using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 20 nm to 120 nm. Met.

"Preparation of high refractive index film"
A polyethylene terephthalate (PET) film T600E-50N (manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material for film formation, and a tin oxide fine particle dispersion paint SM20BP is applied onto this base material using a bar coating method. A coating film was formed to obtain a substrate with a coating film. The thickness of the coating film was adjusted so that the film thickness after curing was 10 μm.
Subsequently, this base material with a coating film was conveyed to a hot air drying oven, dried at 100 ° C. for 3 minutes, and then cured by irradiation with ultraviolet rays (integrated light amount 700 mJ / cm ² ). The high refractive index film of Comparative Example 1 SM20BF was obtained.

[Comparative Example 2]
"Preparation and evaluation of tin oxide dispersion"
30 g of tin oxide fine particles (manufactured by Sumitomo Osaka Cement, primary particle size 10-15 nm), 59.5 g of methyl ethyl ketone as a dispersion medium, and 10.5 g of silane coupling agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a surface treatment agent After mixing 35% by mass with respect to the total amount of tin fine particles, a bead mill using 150 g of glass beads was used, and a dispersion treatment was performed at 3000 rpm for 5 hours. Thereafter, the glass beads were separated by filtering to obtain a tin oxide fine particle dispersion SM35.
As a result of measuring the dispersed particle size of the tin oxide fine particles in this tin oxide fine particle dispersion SM35 using a dynamic light scattering type particle size distribution measuring device (manufactured by Malvern), the dispersed particle size is in the range of 20 nm to 120 nm. there were.

Next, the tin oxide fine particle dispersion SM35 was subjected to ultrasonic dispersion treatment to obtain a tin oxide fine particle dispersion SM35R.
As a result of measuring the dispersed particle size of the tin oxide fine particles in the obtained tin oxide fine particle dispersion SM35R using a dynamic light scattering particle size distribution measuring apparatus (manufactured by Malvern), the dispersed particle size is in the range of 10 nm to 90 nm. It was in.
Further, the haze value of the tin oxide fine particle dispersion SM35R was measured using a spectrophotometer (manufactured by Nippon Denshoku). The sample was placed in a glass cell having an optical path length of 10 mm and a width of 20 mm, and as a result, the haze value was 10.

"Preparation of tin oxide fine particle dispersion paint"
73 g of tin oxide fine particle dispersion SM35R was weighed, and 0.407 g of hexafunctional acrylic UV curable resin DPHA (manufactured by Nippon Kayaku Co., Ltd.) as the uncured resin, and Irgacure 184 (manufactured by Ciba Specialty) as the photoinitiator 0 0.028 g (7% by mass with respect to the resin) was added, and 26.565 g of diacetone alcohol was further added to make the total amount 100 g, and then dispersed and mixed to obtain a tin oxide fine particle dispersed paint SM35RP.

This tin oxide fine particle-dispersed coating SM35RP had a solid content of 30% by mass, and the ratio of the tin oxide fine particles in the solid content was 75% by mass.
In addition, as a result of measuring the dispersed particle diameter of the tin oxide fine particles in the tin oxide fine particle dispersed paint SM35RP using a dynamic light scattering particle size distribution measuring device (manufactured by Malvern), the dispersed particle diameter is in the range of 10 nm to 90 nm. Met.

"Preparation of high refractive index film"
A polyethylene terephthalate (PET) film T600E-50N (manufactured by Mitsubishi Polyester Film Co., Ltd.) is used as a base material for film formation, and a tin oxide fine particle dispersed paint SM35RP is applied onto the base material using a bar coating method. A coating film was formed to obtain a substrate with a coating film. The thickness of the coating film was adjusted so that the film thickness after curing was 10 μm.
Subsequently, this base material with a coating film was conveyed to a hot air drying furnace, dried at 100 ° C. for 3 minutes, and then cured by irradiation with ultraviolet rays (integrated light amount 700 mJ / cm ² ), and the high refractive index film of Comparative Example 2 SM35RF was obtained.

[Evaluation of high refractive index film]
Each high refractive index film produced in Examples 1-5 and Comparative Examples 1-2 was evaluated. Evaluation items and evaluation methods are as follows.

(1) Dispersion particle diameter The dispersion particle diameter of the tin oxide fine particles dispersed in the high refractive index film was measured using a transmission electron microscope (TEM).

(2) Haze value The high refractive index film was cut into a size of 100 mm × 100 mm per substrate, and the haze value was measured in the cross-sectional direction of the film using a spectrophotometer (manufactured by Nippon Denshoku).
Here, since the measured value is the total value of the high refractive index film and the PET base material, the haze value of the PET base material alone is measured, and the haze value 1.4 of the PET base material alone and each measured value The haze value of only the high refractive index film was taken as the difference.

(3) Antistatic performance A high refractive index film was cut into a size of 100 mm × 100 mm per substrate, and surface resistance was measured using a surface resistance meter Hiresta IP (manufactured by Mitsubishi Chemical Corporation).
Here, the surface resistance is less than 1.0 × 10 ¹³ (Ω / □) as “anti-static performance”, and the surface resistance of 1.0 × 10 ¹³ (Ω / □) or more is anti-static performance. “None”.

(4) Refractive index The refractive index was measured with an Abbe refractometer in accordance with Japanese Industrial Standard JIS K 7142 “Method for measuring refractive index of plastic”.
(5) Adhesion Adherence to Japanese Industrial Standard JIS K 5600-5-6 “Paint-General test method-Part 5: Mechanical properties of coating film-Section 6: Adhesion (cross-cut method)” Sexuality was evaluated.
Table 1 shows the production conditions and evaluation results of the high refractive index films of Examples 1 to 5 and Comparative Examples 1 to 3.

  According to Table 1, since the high refractive index films of Examples 1 to 3 have a dispersion particle diameter of tin oxide fine particles in a range of 10 to 90 nm, a transparent film having a low haze value was obtained. Further, since the amount of the surface treatment agent with respect to the tin oxide fine particles is also 30% by mass or less, a high refractive index close to the theoretical value can be obtained, and even if the tin oxide fine particles are contained up to 80% by mass in the solid content, It was possible to secure a sufficient amount of resin for forming the refractive index film, and it was difficult to form pores in the film, and a high refractive index close to the theoretical value and sufficient transparency could be obtained.

Further, in Examples 3 and 5, since the surface treatment was not performed on the tin oxide fine particles, it was found that antistatic performance was also imparted in addition to the effect of increasing the refractive index.
In Examples 4 and 5, since the content of tin oxide fine particles is out of the optimum range, a high refractive index is ensured, but the film quality is inferior to those of Examples 1 to 3.
Furthermore, in the tin oxide fine particle dispersions and the tin oxide fine particle dispersion paints of Examples 1 to 5, since the dispersed particle size of the tin oxide fine particles is in the range of 10 to 90 nm, the haze value is obtained by using these. A low and transparent film could be produced.

On the other hand, in the high refractive index film of Comparative Example 1, the haze value was high and the transparency was impaired. Further, the effect of increasing the refractive index of the resin by adding tin oxide fine particles could not be obtained as the theoretical value.
This is because the dispersed particle diameter is 20 nm to 120 nm, the particle diameter is high and the particle diameter is higher than 90 nm, and the secondary particles include coarse secondary particles. Further, there are voids in the secondary particles. Conceivable.

In the high refractive index film of Comparative Example 2, the haze value was high and the transparency was impaired. Further, the effect of increasing the refractive index of the resin by adding tin oxide fine particles could not be obtained as the theoretical value.
This is because the amount of the surface treatment agent is 35% by mass with respect to the tin oxide fine particles, so that the high refractive index film can be formed even if the proportion of the tin oxide fine particles in the solid content is 75% by mass. This is probably because the amount of the resin was insufficient and pores were formed in the obtained film.
Furthermore, the adhesion of the high refractive index film to the substrate was also poor, but this is thought to be because the absolute amount of resin was insufficient.

Claims (7)

An optical material in which tin oxide fine particles are dispersed in a resin,
The dispersion particle diameter of the tin oxide fine particles is 10 nm or more and 90 nm or less,
An optical material, wherein the surface of the tin oxide fine particles is modified with a surface treatment material of 30% by mass or less of the tin oxide fine particles.   The optical material according to claim 1, wherein the content of the tin oxide fine particles is 20% by mass or more and 80% by mass or less. A tin oxide fine particle dispersion obtained by dispersing tin oxide fine particles in a dispersion medium,
The dispersion particle diameter of the tin oxide fine particles is 10 nm or more and 90 nm or less,
The tin oxide fine particle dispersion is characterized in that the surface of the tin oxide fine particles is modified with a surface treatment material of 30% by mass or less of the tin oxide fine particles. A tin oxide fine particle dispersion paint obtained by dispersing and mixing the tin oxide fine particle dispersion according to claim 3 and an uncured resin,
A tin oxide fine particle dispersed paint, wherein the tin oxide fine particle dispersed in the tin oxide fine particle dispersed paint has a dispersed particle diameter of 10 nm or more and 90 nm or less.   A method for producing an optical material, comprising curing the tin oxide fine particle-dispersed paint according to claim 4.   A high-refractive-index film formed using the optical material according to claim 1.   An antistatic film formed using the optical material according to claim 1.